I have data with latitude and longitude stored in my SQLite database, and I want to get the nearest locations to the parameters I put in (ex. My current location - lat/lng, etc.).
I know that this is possible in MySQL, and I've done quite some research that SQLite needs a custom external function for the Haversine formula (calculating distance on a sphere), but I haven't found anything that is written in Java and works.
Also, if I want to add custom functions, I need the
org.sqlite .jar (for
org.sqlite.Function), and that adds unnecessary size to the app.
The other side of this is, I need the Order by function from SQL, because displaying the distance alone isn't that much of a problem - I already did it in my custom SimpleCursorAdapter, but I can't sort the data, because I don't have the distance column in my database. That would mean updating the database every time the location changes and that's a waste of battery and performance. So if someone has any idea on sorting the cursor with a column that's not in the database, I'd be grateful too!
I know there are tons of Android apps out there that use this function, but can someone please explain the magic.
By the way, I found this alternative: Query to get records based on Radius in SQLite?
It's suggesting to make 4 new columns for cos and sin values of lat and lng, but is there any other, not so redundant way?